Metal gate/high-k stacks are being increasingly used in metal-oxide-semiconductor field-effect-transistors (MOSFETs) in the 10 nm technology node and beyond, however the inventors have observed that many challenges remain in the art. In particular, the development of transistor technology to more advanced nodes (n<10 nm) requires smaller/thinner materials which can lead to gate leakage. Moreover, the inventors have observed that tuning the threshold voltage (Vt) is problematic for transistors with a P type work function which should be close to silicon bandedge (˜5.0 eV).
Accordingly, the inventors have provided improved methods and apparatus for treating high-k materials to modulate the threshold voltage (Vt) thereof.